Method and device for configuring SL HARQ RTT timer in NR V2X

ABSTRACT

Provided are a method for performing wireless communication by a first device, and a device for supporting same. The method may comprise: obtaining a sidelink (SL) discontinuous reception (DRX) configuration including a value of a SL DRX retransmission timer; receiving, from a second device through a physical sidelink control channel (PSCCH), first sidelink control information (SCI) for scheduling of second SCI and a physical sidelink shared channel (PSSCH); receiving, from the second device through the PSSCH, the second SCI and data; determining a value of a SL DRX hybrid automatic repeat request (HARD) round trip time (RTT) timer as zero, based on that information related to a next retransmission resource is not included in the first SCI; and starting the SL DRX retransmission timer.

CROSS-REFERENCE TO RELATED APPLICATION(S)

Pursuant to 35 U.S.C. § 119(e), this application claims the benefit ofU.S. Provisional Patent Application No. 63/274,016, filed on Nov. 1,2021, the contents of which are all hereby incorporated by referenceherein in their entireties.

TECHNICAL FIELD

This disclosure relates to a wireless communication system.

BACKGROUND

Sidelink (SL) communication is a communication scheme in which a directlink is established between User Equipments (UEs) and the UEs exchangevoice and data directly with each other without intervention of anevolved Node B (eNB). SL communication is under consideration as asolution to the overhead of an eNB caused by rapidly increasing datatraffic. Vehicle-to-everything (V2X) refers to a communicationtechnology through which a vehicle exchanges information with anothervehicle, a pedestrian, an object having an infrastructure (or infra)established therein, and so on. The V2X may be divided into 4 types,such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2Xcommunication may be provided via a PC5 interface and/or Uu interface.

Meanwhile, as a wider range of communication devices require largercommunication capacities, the need for mobile broadband communicationthat is more enhanced than the existing Radio Access Technology (RAT) isrising. Accordingly, discussions are made on services and user equipment(UE) that are sensitive to reliability and latency. And, a nextgeneration radio access technology that is based on the enhanced mobilebroadband communication, massive Machine Type Communication (MTC),Ultra-Reliable and Low Latency Communication (URLLC), and so on, may bereferred to as a new radio access technology (RAT) or new radio (NR).Herein, the NR may also support vehicle-to-everything (V2X)communication.

SUMMARY

In one embodiment, provided is a method for performing wirelesscommunication by a first device. The method may comprise: obtaining asidelink (SL) discontinuous reception (DRX) configuration including avalue of a SL DRX retransmission timer; receiving, from a second devicethrough a physical sidelink control channel (PSCCH), first sidelinkcontrol information (SCI) for scheduling of second SCI and a physicalsidelink shared channel (PSSCH); receiving, from the second devicethrough the PSSCH, the second SCI and data; determining a value of a SLDRX hybrid automatic repeat request (HARQ) round trip time (RTT) timeras zero, based on that information related to a next retransmissionresource is not included in the first SCI; and starting the SL DRXretransmission timer.

In one embodiment, provided is a first device adapted to performwireless communication. The first device may comprise: one or morememories storing instructions; one or more transceivers; and one or moreprocessors connected to the one or more memories and the one or moretransceivers. The one or more processors may execute the instructionsto: obtain a sidelink (SL) discontinuous reception (DRX) configurationincluding a value of a SL DRX retransmission timer; control the one ormore transceivers to receive, from a second device through a physicalsidelink control channel (PSCCH), first sidelink control information(SCI) for scheduling of second SCI and a physical sidelink sharedchannel (PSSCH); control the one or more transceivers to receive, fromthe second device through the PSSCH, the second SCI and data; determinea value of a SL DRX hybrid automatic repeat request (HARQ) round triptime (RTT) timer as zero, based on that information related to a nextretransmission resource is not included in the first SCI; and start theSL DRX retransmission timer.

In one embodiment, provided is a processing device adapted to control afirst device. The processing device may comprise: one or moreprocessors; and one or more memories operably connected to the one ormore processors and storing instructions. The one or more processors mayexecute the instructions to: obtain a sidelink (SL) discontinuousreception (DRX) configuration including a value of a SL DRXretransmission timer; receive, from a second device through a physicalsidelink control channel (PSCCH), first sidelink control information(SCI) for scheduling of second SCI and a physical sidelink sharedchannel (PSSCH); receive, from the second device through the PSSCH, thesecond SCI and data; determine a value of a SL DRX hybrid automaticrepeat request (HARQ) round trip time (RTT) timer as zero, based on thatinformation related to a next retransmission resource is not included inthe first SCI; and start the SL DRX retransmission timer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structure of an NR system, based on an embodiment of thepresent disclosure.

FIG. 2 shows a radio protocol architecture, based on an embodiment ofthe present disclosure.

FIG. 3 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure.

FIG. 4 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure.

FIG. 5 shows an example of a BWP, based on an embodiment of the presentdisclosure.

FIG. 6 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure.

FIG. 7 shows three cast types, based on an embodiment of the presentdisclosure.

FIG. 8 shows a method for an RX UE to perform a power saving operationbased on SCI, based on an embodiment of the present disclosure.

FIG. 9 shows a procedure for an RX UE and/or a TX UE to perform SLcommunication based on a SL DRX configuration, based on an embodiment ofthe present disclosure.

FIG. 10 shows a method for performing a power saving operation based onresource reservation information included in SCI, based on an embodimentof the present disclosure.

FIG. 11 shows a method for performing wireless communication by a firstdevice, based on an embodiment of the present disclosure.

FIG. 12 shows a method for performing wireless communication by a seconddevice, based on an embodiment of the present disclosure.

FIG. 13 shows a communication system 1, based on an embodiment of thepresent disclosure.

FIG. 14 shows wireless devices, based on an embodiment of the presentdisclosure.

FIG. 15 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

FIG. 16 shows another example of a wireless device, based on anembodiment of the present disclosure.

FIG. 17 shows a hand-held device, based on an embodiment of the presentdisclosure.

FIG. 18 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure.

DETAILED DESCRIPTION

In the present disclosure, “A or B” may mean “only A”, “only B” or “bothA and B.” In other words, in the present disclosure, “A or B” may beinterpreted as “A and/or B”. For example, in the present disclosure, “A,B, or C” may mean “only A”, “only B”, “only C”, or “any combination ofA, B, C”.

A slash (/) or comma used in the present disclosure may mean “and/or”.For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean“only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean“A, B, or C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B”, or “both A and B”. In addition, in the present disclosure, theexpression “at least one of A or B” or “at least one of A and/or B” maybe interpreted as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present disclosure may mean “forexample”. Specifically, when indicated as “control information (PDCCH)”,it may mean that “PDCCH” is proposed as an example of the “controlinformation”. In other words, the “control information” of the presentdisclosure is not limited to “PDCCH”, and “PDCCH” may be proposed as anexample of the “control information”. In addition, when indicated as“control information (i.e., PDCCH)”, it may also mean that “PDCCH” isproposed as an example of the “control information”.

In the following description, ‘when, if, or in case of’ may be replacedwith ‘based on’.

A technical feature described individually in one figure in the presentdisclosure may be individually implemented, or may be simultaneouslyimplemented.

In the present disclosure, a higher layer parameter may be a parameterwhich is configured, pre-configured or pre-defined for a UE. Forexample, a base station or a network may transmit the higher layerparameter to the UE. For example, the higher layer parameter may betransmitted through radio resource control (RRC) signaling or mediumaccess control (MAC) signaling.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-2000. The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), and so on. IEEE 802.16m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRA is part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features according to anembodiment of the present disclosure will not be limited only to this.

FIG. 1 shows a structure of an NR system, based on an embodiment of thepresent disclosure. The embodiment of FIG. 1 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 1 , a next generation—radio access network (NG-RAN)may include a BS 20 providing a UE 10 with a user plane and controlplane protocol termination. For example, the BS 20 may include a nextgeneration-Node B (gNB) and/or an evolved-NodeB (eNB). For example, theUE 10 may be fixed or mobile and may be referred to as other terms, suchas a mobile station (MS), a user terminal (UT), a subscriber station(SS), a mobile terminal (MT), wireless device, and so on. For example,the BS may be referred to as a fixed station which communicates with theUE 10 and may be referred to as other terms, such as a base transceiversystem (BTS), an access point (AP), and so on.

The embodiment of FIG. 1 exemplifies a case where only the gNB isincluded. The BSs 20 may be connected to one another via Xn interface.The BS 20 may be connected to one another via 5th generation (5G) corenetwork (5GC) and NG interface. More specifically, the BSs 20 may beconnected to an access and mobility management function (AMF) 30 viaNG-C interface, and may be connected to a user plane function (UPF) 30via NG-U interface.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (layer 1, L1), a second layer (layer 2,L2), and a third layer (layer 3, L3) based on the lower three layers ofthe open system interconnection (OSI) model that is well-known in thecommunication system. Among them, a physical (PHY) layer belonging tothe first layer provides an information transfer service by using aphysical channel, and a radio resource control (RRC) layer belonging tothe third layer serves to control a radio resource between the UE andthe network. For this, the RRC layer exchanges an RRC message betweenthe UE and the BS.

FIG. 2 shows a radio protocol architecture, based on an embodiment ofthe present disclosure. The embodiment of FIG. 2 may be combined withvarious embodiments of the present disclosure. Specifically, (a) of FIG.2 shows a radio protocol stack of a user plane for Uu communication, and(b) of FIG. 2 shows a radio protocol stack of a control plane for Uucommunication. (c) of FIG. 2 shows a radio protocol stack of a userplane for SL communication, and (d) of FIG. 2 shows a radio protocolstack of a control plane for SL communication.

Referring to FIG. 2 , a physical layer provides an upper layer with aninformation transfer service through a physical channel. The physicallayer is connected to a medium access control (MAC) layer which is anupper layer of the physical layer through a transport channel. Data istransferred between the MAC layer and the physical layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transmitted through a radiointerface.

Between different physical layers, i.e., a physical layer of atransmitter and a physical layer of a receiver, data are transferredthrough the physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRadio Link Control Service Data Unit (RLC SDU). In order to ensurediverse quality of service (QoS) required by a radio bearer (RB), theRLC layer provides three types of operation modes, i.e., a transparentmode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM).An AM RLC provides error correction through an automatic repeat request(ARQ).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of RBs. The RB is a logicalpath provided by the first layer (i.e., the physical layer or the PHYlayer) and the second layer (i.e., a MAC layer, an RLC layer, a packetdata convergence protocol (PDCP) layer, and a service data adaptationprotocol (SDAP) layer) for data delivery between the UE and the network.

Functions of a packet data convergence protocol (PDCP) layer in the userplane include user data delivery, header compression, and ciphering.Functions of a PDCP layer in the control plane include control-planedata delivery and ciphering/integrity protection.

A service data adaptation protocol (SDAP) layer is defined only in auser plane. The SDAP layer performs mapping between a Quality of Service(QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) markingin both DL and UL packets.

The configuration of the RB implies a process for specifying a radioprotocol layer and channel properties to provide a particular serviceand for determining respective detailed parameters and operations. TheRB can be classified into two types, i.e., a signaling RB (SRB) and adata RB (DRB). The SRB is used as a path for transmitting an RRC messagein the control plane. The DRB is used as a path for transmitting userdata in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in an RRC_IDLE state. In case of the NR, anRRC_INACTIVE state is additionally defined, and a UE being in theRRC_INACTIVE state may maintain its connection with a core networkwhereas its connection with the BS is released.

Data is transmitted from the network to the UE through a downlinktransport channel. Examples of the downlink transport channel include abroadcast channel (BCH) for transmitting system information and adownlink-shared channel (SCH) for transmitting user traffic or controlmessages. Traffic of downlink multicast or broadcast services or thecontrol messages can be transmitted on the downlink-SCH or an additionaldownlink multicast channel (MCH). Data is transmitted from the UE to thenetwork through an uplink transport channel. Examples of the uplinktransport channel include a random access channel (RACH) fortransmitting an initial control message and an uplink SCH fortransmitting user traffic or control messages.

Examples of logical channels belonging to a higher channel of thetransport channel and mapped onto the transport channels include abroadcast channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

FIG. 3 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure. The embodiment of FIG. 3 may becombined with various embodiments of the present disclosure.

Referring to FIG. 3 , in the NR, a radio frame may be used forperforming uplink and downlink transmission. A radio frame has a lengthof 10 ms and may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five 1 ms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined based on subcarrier spacing (SCS). Each slotmay include 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and a SingleCarrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM(DFT-s-OFDM) symbol).

Table 1 shown below represents an example of a number of symbols perslot (N^(slot) _(symb)), a number slots per frame (N^(frame,u) _(slot)),and a number of slots per subframe (N^(subframe,u) _(slot)) based on anSCS configuration (u), in a case where a normal CP is used.

TABLE 1 SCS (15*2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 15 KHz (u = 0) 14 10 1 30 KHz (u = 1) 14 20 2 60KHz (u = 2) 14 40 4 120 KHz (u = 3) 14 80 8 240 KHz (u = 4) 14 160 16

Table 2 shows an example of a number of symbols per slot, a number ofslots per frame, and a number of slots per subframe based on the SCS, ina case where an extended CP is used.

TABLE 2 SCS (15*2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 60 KHz (u = 2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells.

In the NR, multiple numerologies or SCSs for supporting diverse 5Gservices may be supported. For example, in case an SCS is 15 kHz, a widearea of the conventional cellular bands may be supported, and, in casean SCS is 30 kHz/60 kHz a dense-urban, lower latency, wider carrierbandwidth may be supported. In case the SCS is 60 kHz or higher, abandwidth that is greater than 24.25 GHz may be used in order toovercome phase noise.

An NR frequency band may be defined as two different types of frequencyranges. The two different types of frequency ranges may be FR1 and FR2.The values of the frequency ranges may be changed (or varied), and, forexample, the two different types of frequency ranges may be as shownbelow in Table 3. Among the frequency ranges that are used in an NRsystem, FR1 may mean a “sub 6 GHz range”, and FR2 may mean an “above 6GHz range” and may also be referred to as a millimeter wave (mmW).

TABLE 3 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing (SCS) FR1 450 MHz-6000 MHz 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

As described above, the values of the frequency ranges in the NR systemmay be changed (or varied). For example, as shown below in Table 4, FR1may include a band within a range of 410 MHz to 7125 MHz. Morespecifically, FR1 may include a frequency band of 6 GHz (or 5850, 5900,5925 MHz, and so on) and higher. For example, a frequency band of 6 GHz(or 5850, 5900, 5925 MHz, and so on) and higher being included in FR1mat include an unlicensed band. The unlicensed band may be used fordiverse purposes, e.g., the unlicensed band for vehicle-specificcommunication (e.g., automated driving).

TABLE 4 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing (SCS) FR1 410 MHz-7125 MHz 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 4 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure. The embodiment of FIG. 4 may becombined with various embodiments of the present disclosure.

Referring to FIG. 4 , a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP, one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (Physical)Resource Blocks ((P)RBs) in the frequency domain, and the BWP maycorrespond to one numerology (e.g., SCS, CP length, and so on). Acarrier may include a maximum of N number BWPs (e.g., 5 BWPs). Datacommunication may be performed via an activated BWP. Each element may bereferred to as a Resource Element (RE) within a resource grid and onecomplex symbol may be mapped to each element.

Hereinafter, a bandwidth part (BWP) and a carrier will be described.

The BWP may be a set of consecutive physical resource blocks (PRBs) in agiven numerology. The PRB may be selected from consecutive sub-sets ofcommon resource blocks (CRBs) for the given numerology on a givencarrier.

For example, the BWP may be at least any one of an active BWP, aninitial BWP, and/or a default BWP. For example, the UE may not monitordownlink radio link quality in a DL BWP other than an active DL BWP on aprimary cell (PCell). For example, the UE may not receive PDCCH,physical downlink shared channel (PDSCH), or channel stateinformation—reference signal (CSI-RS) (excluding RRM) outside the activeDL BWP. For example, the UE may not trigger a channel state information(CSI) report for the inactive DL BWP. For example, the UE may nottransmit physical uplink control channel (PUCCH) or physical uplinkshared channel (PUSCH) outside an active UL BWP. For example, in adownlink case, the initial BWP may be given as a consecutive RB set fora remaining minimum system information (RMSI) control resource set(CORESET) (configured by physical broadcast channel (PBCH)). Forexample, in an uplink case, the initial BWP may be given by systeminformation block (SIB) for a random access procedure. For example, thedefault BWP may be configured by a higher layer. For example, an initialvalue of the default BWP may be an initial DL BWP. For energy saving, ifthe UE fails to detect downlink control information (DCI) during aspecific period, the UE may switch the active BWP of the UE to thedefault BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used intransmission and reception. For example, a transmitting UE may transmita SL channel or a SL signal on a specific BWP, and a receiving UE mayreceive the SL channel or the SL signal on the specific BWP. In alicensed carrier, the SL BWP may be defined separately from a Uu BWP,and the SL BWP may have configuration signaling separate from the UuBWP. For example, the UE may receive a configuration for the SL BWP fromthe BS/network. For example, the UE may receive a configuration for theUu BWP from the BS/network. The SL BWP may be (pre-)configured in acarrier with respect to an out-of-coverage NR V2X UE and an RRC_IDLE UE.For the UE in the RRC_CONNECTED mode, at least one SL BWP may beactivated in the carrier.

FIG. 5 shows an example of a BWP, based on an embodiment of the presentdisclosure. The embodiment of FIG. 5 may be combined with variousembodiments of the present disclosure. It is assumed in the embodimentof FIG. 5 that the number of BWPs is 3.

Referring to FIG. 5 , a common resource block (CRB) may be a carrierresource block numbered from one end of a carrier band to the other endthereof. In addition, the PRB may be a resource block numbered withineach BWP. A point A may indicate a common reference point for a resourceblock grid.

The BWP may be configured by a point A, an offset N^(start) _(BWP) fromthe point A, and a bandwidth N^(size) _(BWP). For example, the point Amay be an external reference point of a PRB of a carrier in which asubcarrier 0 of all numerologies (e.g., all numerologies supported by anetwork on that carrier) is aligned. For example, the offset may be aPRB interval between a lowest subcarrier and the point A in a givennumerology. For example, the bandwidth may be the number of PRBs in thegiven numerology.

Hereinafter, V2X or SL communication will be described.

A sidelink synchronization signal (SLSS) may include a primary sidelinksynchronization signal (PSSS) and a secondary sidelink synchronizationsignal (SSSS), as a SL-specific sequence. The PSSS may be referred to asa sidelink primary synchronization signal (S-PSS), and the SSSS may bereferred to as a sidelink secondary synchronization signal (S-SSS). Forexample, length-127 M-sequences may be used for the S-PSS, andlength-127 gold sequences may be used for the S-SSS. For example, a UEmay use the S-PSS for initial signal detection and for synchronizationacquisition. For example, the UE may use the S-PSS and the S-SSS foracquisition of detailed synchronization and for detection of asynchronization signal ID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel for transmitting default (system) information which must befirst known by the UE before SL signal transmission/reception. Forexample, the default information may be information related to SLSS, aduplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL)configuration, information related to a resource pool, a type of anapplication related to the SLSS, a subframe offset, broadcastinformation, or the like. For example, for evaluation of PSBCHperformance, in NR V2X, a payload size of the PSBCH may be 56 bitsincluding 24-bit cyclic redundancy check (CRC).

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., SL synchronization signal (SS)/PSBCH block, hereinafter,sidelink-synchronization signal block (S-SSB)) supporting periodicaltransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in a carrier, and a transmission bandwidth mayexist within a (pre-)configured sidelink (SL) BWP. For example, theS-SSB may have a bandwidth of 11 resource blocks (RBs). For example, thePSBCH may exist across 11 RBs. In addition, a frequency position of theS-SSB may be (pre-)configured. Accordingly, the UE does not have toperform hypothesis detection at frequency to discover the S-SSB in thecarrier.

FIG. 6 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure. The embodiment of FIG. 6 may be combined with variousembodiments of the present disclosure. In various embodiments of thepresent disclosure, the transmission mode may be called a mode or aresource allocation mode. Hereinafter, for convenience of explanation,in LTE, the transmission mode may be called an LTE transmission mode. InNR, the transmission mode may be called an NR resource allocation mode.

For example, (a) of FIG. 6 shows a UE operation related to an LTEtransmission mode 1 or an LTE transmission mode 3. Alternatively, forexample, (a) of FIG. 6 shows a UE operation related to an NR resourceallocation mode 1. For example, the LTE transmission mode 1 may beapplied to general SL communication, and the LTE transmission mode 3 maybe applied to V2X communication.

For example, (b) of FIG. 6 shows a UE operation related to an LTEtransmission mode 2 or an LTE transmission mode 4. Alternatively, forexample, (b) of FIG. 6 shows a UE operation related to an NR resourceallocation mode 2.

Referring to (a) of FIG. 6 , in the LTE transmission mode 1, the LTEtransmission mode 3, or the NR resource allocation mode 1, a basestation may schedule SL resource(s) to be used by a UE for SLtransmission. For example, in step S600, a base station may transmitinformation related to SL resource(s) and/or information related to ULresource(s) to a first UE. For example, the UL resource(s) may includePUCCH resource(s) and/or PUSCH resource(s). For example, the ULresource(s) may be resource(s) for reporting SL HARQ feedback to thebase station.

For example, the first UE may receive information related to dynamicgrant (DG) resource(s) and/or information related to configured grant(CG) resource(s) from the base station. For example, the CG resource(s)may include CG type 1 resource(s) or CG type 2 resource(s). In thepresent disclosure, the DG resource(s) may be resource(s)configured/allocated by the base station to the first UE through adownlink control information (DCI). In the present disclosure, the CGresource(s) may be (periodic) resource(s) configured/allocated by thebase station to the first UE through a DCI and/or an RRC message. Forexample, in the case of the CG type 1 resource(s), the base station maytransmit an RRC message including information related to CG resource(s)to the first UE. For example, in the case of the CG type 2 resource(s),the base station may transmit an RRC message including informationrelated to CG resource(s) to the first UE, and the base station maytransmit a DCI related to activation or release of the CG resource(s) tothe first UE.

In step S610, the first UE may transmit a PSCCH (e.g., sidelink controlinformation (SCI) or 1^(st)-stage SCI) to a second UE based on theresource scheduling. In step S620, the first UE may transmit a PSSCH(e.g., 2^(nd)-stage SCI, MAC PDU, data, etc.) related to the PSCCH tothe second UE. In step S630, the first UE may receive a PSFCH related tothe PSCCH/PSSCH from the second UE. For example, HARQ feedbackinformation (e.g., NACK information or ACK information) may be receivedfrom the second UE through the PSFCH. In step S640, the first UE maytransmit/report HARQ feedback information to the base station throughthe PUCCH or the PUSCH. For example, the HARQ feedback informationreported to the base station may be information generated by the firstUE based on the HARQ feedback information received from the second UE.For example, the HARQ feedback information reported to the base stationmay be information generated by the first UE based on a pre-configuredrule. For example, the DCI may be a DCI for SL scheduling. For example,a format of the DCI may be a DCI format 3_0 or a DCI format 3_1.

Hereinafter, an example of DCI format 3_0 will be described.

DCI format 3_0 is used for scheduling of NR PSCCH and NR PSSCH in onecell.

The following information is transmitted by means of the DCI format 3_0with CRC scrambled by SL-RNTI or SL-CS-RNTI:

-   -   Resource pool index—ceiling (log₂ I) bits, where I is the number        of resource pools for transmission configured by the higher        layer parameter sl-TxPoolScheduling.    -   Time gap—3 bits determined by higher layer parameter        sl-DCI-ToSL-Trans    -   HARQ process number—4 bits    -   New data indicator—1 bit    -   Lowest index of the subchannel allocation to the initial        transmission—ceiling (log₂(N^(SL) _(subChannel))) bits    -   SCI format 1-A fields: frequency resource assignment, time        resource assignment    -   PSFCH-to-HARQ feedback timing indicator—ceiling (log₂        N_(fb_timing)) bits, where N_(fb_timing) is the number of        entries in the higher layer parameter sl-PSFCH-ToPUCCH.    -   PUCCH resource indicator—3 bits    -   Configuration index—0 bit if the UE is not configured to monitor        DCI format 3_0 with CRC scrambled by SL-CS-RNTI; otherwise 3        bits. If the UE is configured to monitor DCI format 3_0 with CRC        scrambled by SL-CS-RNTI, this field is reserved for DCI format        3_0 with CRC scrambled by SL-RNTI.    -   Counter sidelink assignment index—2 bits, 2 bits if the UE is        configured with pdsch-HARQ-ACK-Codebook=dynamic, 2 bits if the        UE is configured with pdsch-HARQ-ACK-Codebook=semi-static    -   Padding bits, if required

Referring to (b) of FIG. 6 , in the LTE transmission mode 2, the LTEtransmission mode 4, or the NR resource allocation mode 2, a UE maydetermine SL transmission resource(s) within SL resource(s) configuredby a base station/network or pre-configured SL resource(s). For example,the configured SL resource(s) or the pre-configured SL resource(s) maybe a resource pool. For example, the UE may autonomously select orschedule resource(s) for SL transmission. For example, the UE mayperform SL communication by autonomously selecting resource(s) withinthe configured resource pool. For example, the UE may autonomouslyselect resource(s) within a selection window by performing a sensingprocedure and a resource (re)selection procedure. For example, thesensing may be performed in a unit of subchannel(s). For example, instep S610, a first UE which has selected resource(s) from a resourcepool by itself may transmit a PSCCH (e.g., sidelink control information(SCI) or 1^(st)-stage SCI) to a second UE by using the resource(s). Instep S620, the first UE may transmit a PSSCH (e.g., 2^(nd)-stage SCI,MAC PDU, data, etc.) related to the PSCCH to the second UE. In stepS630, the first UE may receive a PSFCH related to the PSCCH/PSSCH fromthe second UE.

Referring to (a) or (b) of FIG. 6 , for example, the first UE maytransmit a SCI to the second UE through the PSCCH. Alternatively, forexample, the first UE may transmit two consecutive SCIs (e.g., 2-stageSCI) to the second UE through the PSCCH and/or the PSSCH. In this case,the second UE may decode two consecutive SCIs (e.g., 2-stage SCI) toreceive the PSSCH from the first UE. In the present disclosure, a SCItransmitted through a PSCCH may be referred to as a 1^(st) SCI, a firstSCI, a 1^(st)-stage SCI or a 1^(st)-stage SCI format, and a SCItransmitted through a PSSCH may be referred to as a 2^(nd) SCI, a secondSCI, a 2^(nd)-stage SCI or a 2^(nd)-stage SCI format. For example, the1^(st)-stage SCI format may include a SCI format 1-A, and the2^(nd)-stage SCI format may include a SCI format 2-A and/or a SCI format2-B.

Hereinafter, an example of SCI format 1-A will be described.

SCI format 1-A is used for the scheduling of PSSCH and 2^(nd)-stage-SCIon PSSCH.

The following information is transmitted by means of the SCI format 1-A:

-   -   Priority—3 bits    -   Frequency resource assignment—ceiling (log₂ (N^(SL)        _(subChannel)(N^(SL) _(subChannel)+1)/2)) bits when the value of        the higher layer parameter sl-MaxNumPerReserve is configured to        2; otherwise ceiling log₂(N^(SL) _(subChannel)(N^(SL)        _(subChannel)+1)(2N^(SL) _(subChannel)+1)/6) bits when the value        of the higher layer parameter sl-MaxNumPerReserve is configured        to 3    -   Time resource assignment—5 bits when the value of the higher        layer parameter sl-MaxNumPerReserve is configured to 2;        otherwise 9 bits when the value of the higher layer parameter        sl-MaxNumPerReserve is configured to 3    -   Resource reservation period—ceiling (log₂ N_(rsvp_period)) bits,        where N_(rsv_period) is the number of entries in the higher        layer parameter sl-ResourceReservePeriodList, if higher layer        parameter sl-MultiReserveResource is configured; 0 bit otherwise    -   DMRS pattern—ceiling (log₂ N_(pattern)) bits, where N_(pattern)        is the number of DMRS patterns configured by higher layer        parameter sl-PSSCH-DMRS-TimePatternList    -   2^(nd)-stage SCI format—2 bits as defined in Table 5    -   Beta_offset indicator—2 bits as provided by higher layer        parameter sl-BetaOffsets2ndSCI    -   Number of DMRS port—1 bit as defined in Table 6    -   Modulation and coding scheme—5 bits    -   Additional MCS table indicator—1 bit if one MCS table is        configured by higher layer parameter sl-Additional-MCS-Table; 2        bits if two MCS tables are configured by higher layer parameter        sl-Additional-MCS-Table; 0 bit otherwise    -   PSFCH overhead indication—1 bit if higher layer parameter        sl-PSFCH-Period=2 or 4; 0 bit otherwise    -   Reserved—a number of bits as determined by higher layer        parameter sl-NumReservedBits, with value set to zero.

TABLE 5 Value of 2nd-stage SCI format field 2nd-stage SCI format 00 SCIformat 2-A 01 SCI format 2-B 10 Reserved 11 Reserved

TABLE 6 Value of the Number of DMRS port field Antenna ports 0 1000 11000 and 1001

Hereinafter, an example of SCI format 2-A will be described.

SCI format 2-A is used for the decoding of PSSCH, with HARQ operationwhen HARQ-ACK information includes ACK or NACK, when HARQ-ACKinformation includes only NACK, or when there is no feedback of HARQ-ACKinformation.

The following information is transmitted by means of the SCI format 2-A:

-   -   HARQ process number—4 bits    -   New data indicator—1 bit    -   Redundancy version—2 bits    -   Source ID—8 bits    -   Destination ID—16 bits    -   HARQ feedback enabled/disabled indicator—1 bit    -   Cast type indicator—2 bits as defined in Table 7    -   CSI request—1 bit

TABLE 7 Value of Cast type indicator Cast type 00 Broadcast 01 Groupcastwhen HARQ-ACK information includes ACK or NACK 10 Unicast 11 Groupcastwhen HARQ-ACK information includes only NACK

Hereinafter, an example of SCI format 2-B will be described.

SCI format 2-B is used for the decoding of PSSCH, with HARQ operationwhen HARQ-ACK information includes only NACK, or when there is nofeedback of HARQ-ACK information.

The following information is transmitted by means of the SCI format 2-B:

-   -   HARQ process number—4 bits    -   New data indicator—1 bit    -   Redundancy version—2 bits    -   Source ID—8 bits    -   Destination ID—16 bits    -   HARQ feedback enabled/disabled indicator—1 bit    -   Zone ID—12 bits    -   Communication range requirement—4 bits determined by higher        layer parameter sl-ZoneConfigMCR-Index

Referring to (a) or (b) of FIG. 6 , in step S630, the first UE mayreceive the PSFCH. For example, the first UE and the second UE maydetermine a PSFCH resource, and the second UE may transmit HARQ feedbackto the first UE using the PSFCH resource.

Referring to (a) of FIG. 6 , in step S640, the first UE may transmit SLHARQ feedback to the base station through the PUCCH and/or the PUSCH.

FIG. 7 shows three cast types, based on an embodiment of the presentdisclosure. The embodiment of FIG. 7 may be combined with variousembodiments of the present disclosure. Specifically, (a) of FIG. 7 showsbroadcast-type SL communication, (b) of FIG. 7 shows unicast type-SLcommunication, and (c) of FIG. 7 shows groupcast-type SL communication.In case of the unicast-type SL communication, a UE may performone-to-one communication with respect to another UE. In case of thegroupcast-type SL transmission, the UE may perform SL communication withrespect to one or more UEs in a group to which the UE belongs. Invarious embodiments of the present disclosure, SL groupcastcommunication may be replaced with SL multicast communication, SLone-to-many communication, or the like.

Hereinafter, a hybrid automatic repeat request (HARQ) procedure will bedescribed.

For example, the SL HARQ feedback may be enabled for unicast. In thiscase, in a non-code block group (non-CBG) operation, if the receiving UEdecodes a PSCCH of which a target is the receiving UE and if thereceiving UE successfully decodes a transport block related to thePSCCH, the receiving UE may generate HARQ-ACK. In addition, thereceiving UE may transmit the HARQ-ACK to the transmitting UE.Otherwise, if the receiving UE cannot successfully decode the transportblock after decoding the PSCCH of which the target is the receiving UE,the receiving UE may generate the HARQ-NACK. In addition, the receivingUE may transmit HARQ-NACK to the transmitting UE.

For example, the SL HARQ feedback may be enabled for groupcast. Forexample, in the non-CBG operation, two HARQ feedback options may besupported for groupcast.

(1) Groupcast option 1: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of a transport block related to the PSCCH, the receiving UE maytransmit HARQ-NACK to the transmitting UE through a PSFCH. Otherwise, ifthe receiving UE decodes the PSCCH of which the target is the receivingUE and if the receiving UE successfully decodes the transport blockrelated to the PSCCH, the receiving UE may not transmit the HARQ-ACK tothe transmitting UE.

(2) Groupcast option 2: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of the transport block related to the PSCCH, the receiving UEmay transmit HARQ-NACK to the transmitting UE through the PSFCH. Inaddition, if the receiving UE decodes the PSCCH of which the target isthe receiving UE and if the receiving UE successfully decodes thetransport block related to the PSCCH, the receiving UE may transmit theHARQ-ACK to the transmitting UE through the PSFCH.

For example, if the groupcast option 1 is used in the SL HARQ feedback,all UEs performing groupcast communication may share a PSFCH resource.For example, UEs belonging to the same group may transmit HARQ feedbackby using the same PSFCH resource.

For example, if the groupcast option 2 is used in the SL HARQ feedback,each UE performing groupcast communication may use a different PSFCHresource for HARQ feedback transmission. For example, UEs belonging tothe same group may transmit HARQ feedback by using different PSFCHresources.

In the present disclosure, HARQ-ACK may be referred to as ACK, ACKinformation, or positive-ACK information, and HARQ-NACK may be referredto as NACK, NACK information, or negative-ACK information.

Hereinafter, UE procedure for reporting HARQ-ACK on sidelink will bedescribed.

A UE can be indicated by an SCI format scheduling a PSSCH reception, inone or more sub-channels from a number of N^(PSSCH) _(subch)sub-channels, to transmit a PSFCH with HARQ-ACK information in responseto the PSSCH reception. The UE provides HARQ-ACK information thatincludes ACK or NACK, or only NACK.

A UE can be provided, by sl-PSFCH-Period-r16, a number of slots in aresource pool for a period of PSFCH transmission occasion resources. Ifthe number is zero, PSFCH transmissions from the UE in the resource poolare disabled. A UE expects that a slot t′_(k) ^(SL) (0≤k<T_(max)) has aPSFCH transmission occasion resource if k mod N^(PSFCH) _(PSSCH)=0,where t′_(k) ^(SL) is a slot that belongs to the resource pool, T′_(max)is a number of slots that belong to the resource pool within 10240 msec,and N^(PSFCH) _(PSSCH) is provided by sl-PSFCH-Period-r16. A UE may beindicated by higher layers to not transmit a PSFCH in response to aPSSCH reception. If a UE receives a PSSCH in a resource pool and theHARQ feedback enabled/disabled indicator field in an associated SCIformat 2-A or a SCI format 2-B has value 1, the UE provides the HARQ-ACKinformation in a PSFCH transmission in the resource pool. The UEtransmits the PSFCH in a first slot that includes PSFCH resources and isat least a number of slots, provided by sl-MinTimeGapPSFCH-r16, of theresource pool after a last slot of the PSSCH reception.

A UE is provided by sl-PSFCH-RB-Set-r16 a set of M^(PSFCH) _(PRB,set)PRBs in a resource pool for PSFCH transmission in a PRB of the resourcepool. For a number of N_(subch) sub-channels for the resource pool,provided by sl-NumSubchannel, and a number of PSSCH slots associatedwith a PSFCH slot that is less than or equal to N^(PSFCH) _(PSSCH), theUE allocates the [(i+j·N^(PSFCH) _(PSSCH))·M^(PSFCH) _(subch,slot),(i+1+j·N^(PSFCH) _(PSSCH))·M^(PSFCH) _(subch,slot)−1] PRBs from theM_(PRB,set) ^(PSFCH) PRBs to slot i among the PSSCH slots associatedwith the PSFCH slot and sub-channel j, where M^(PSFCH)_(subch,slot)=M^(PSFCH) _(PRB,set)/(N_(subch)·N^(PSFCH) _(PSSCH)),0≤i<N^(PSFCH) _(PSSCH), 0≤j<N_(subch), and the allocation starts in anascending order of i and continues in an ascending order of j. The UEexpects that M^(PSFCH) _(PRB,set) is a multiple of N_(subch)·N^(PSFCH)_(PSSCH).

A UE determines a number of PSFCH resources available for multiplexingHARQ-ACK information in a PSFCH transmission as R^(PSFCH)_(PRB,CS)=N^(PSFCH) _(type)·M^(PSFCH) _(subch,slot)·N^(PSFCH) _(CS)where N^(PSFCH) _(CS) is a number of cyclic shift pairs for the resourcepool and, based on an indication by higher layers,

-   -   N^(PSFCH) _(type)=1 and the M^(PSFCH) _(subch,slot) PRBs are        associated with the starting sub-channel of the corresponding        PSSCH    -   N^(PSFCH) _(type)=N^(PSSCH) _(subch) and the N^(PSSCH)        _(subch)·M^(PSFCH) _(subch,slot) PRBs are associated with one or        more sub-channels from the N^(PSSCH) _(subch) sub-channels of        the corresponding PSSCH

The PSFCH resources are first indexed according to an ascending order ofthe PRB index, from the N^(PSFCH) _(type)·M^(PSFCH) _(subch,slot) PRBs,and then according to an ascending order of the cyclic shift pair indexfrom the N^(PSFCH) _(CS) cyclic shift pairs.

A UE determines an index of a PSFCH resource for a PSFCH transmission inresponse to a PSSCH reception as (P_(ID)+M_(ID))_(mod) R^(PSFCH)_(PRB,CS) where P_(ID) is a physical layer source ID provided by SCIformat 2-A or 2-B scheduling the PSSCH reception, and M_(ID) is theidentity of the UE receiving the PSSCH as indicated by higher layers ifthe UE detects a SCI format 2-A with Cast type indicator field value of“01”; otherwise, M_(ID) is zero.

A UE determines a m₀ value, for computing a value of cyclic shift α,from a cyclic shift pair index corresponding to a PSFCH resource indexand from N^(PSFCH) _(CS) using Table 8.

TABLE 8 m₀ cyclic shift cyclic shift cyclic shift cyclic shift cyclicshift cyclic shift N^(PSFCH) _(CS) pair index 0 pair index 1 pair index2 pair index 3 pair index 4 pair index 5 1 0 — — — — — 2 0 3 — — — — 3 02 4 — — — 6 0 1 2 3 4 5

A UE determines a m_(cs) value, for computing a value or cyclic shift α,as in Table 9 if the UE detects a SCI format 2-A with Cast typeindicator field value of “01” or “10”, or as in Table 10 if the UEdetects a SCI format 2-B or a SCI format 2-A with Cast type indicatorfield value of “11”. The UE applies one cyclic shift from a cyclic shiftpair to a sequence used for the PSFCH transmission.

TABLE 9 HARQ-ACK Value 0 (NACK) 1 (ACK) Sequence cyclic shift 0 6

TABLE 10 HARQ-ACK Value 0 (NACK) 1 (ACK) Sequence cyclic shift 0 N/A

Meanwhile, a power saving operation of the UE is not supported in NR V2Xof release 16, and the power saving operation of the UE (e.g., PowerSaving UE) will be supported from NR V2X of release 17.

For the power saving operation (e.g., sidelink DRX operation) of the UE,a sidelink DRX configuration (e.g., sidelink DRX cycle, sidelink DRXonduration, sidelink DRX offduration, timers for supporting the sidelinkDRX operation, etc.) to be used by the Power Saving UE (P-UE) should bedefined, and operations of the transmitting (TX) UE and the receiving(RX) UE in on-duration (e.g., duration where sidelinkreception/transmission can be performed)/offduration (e.g., durationoperating in sleep mode) should be defined.

FIG. 8 shows a method for an RX UE to perform a power saving operationbased on SCI, based on an embodiment of the present disclosure. Theembodiment of FIG. 8 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 8 , if the RX UE supporting a sidelink DRX operationreceives SCI (SCI including reserved transmission scheduling informationfor PSSCH (i.e., sidelink data) reception) transmitted by the TX UE, theRX UE may monitor (or receive) a PSCCH/PSSCH transmitted by the TX UE byremaining an active state until the RX UE receives all PSCCH/PSSCHtransmitted by the TX UE using the reserved transmission resource.

Meanwhile, the RX UE may perform a power saving operation based onresource reservation information (e.g., time resource assignmentinformation and/or resource reservation period information) included inSCI transmitted by the TX UE. For example, the RX UE which has receivedSCI including information related to a second SL resource (i.e., thenext retransmission resource) on a first SL resource may start a SL DRXhybrid automatic repeat request (HARQ) round trip time (RTT) timer afterthe time domain of the first SL resource. In addition, the RX UE maystop the SL DRX HARQ RTT timer before the time domain of the second SLresource (i.e., the next retransmission resource). Through this, the RXUE can obtain a power saving gain. Meanwhile, even if SCI does notinclude information related to the second SL resource (i.e., the nextretransmission resource), the RX UE needs to determine a value of the SLDRX HARQ RTT timer. Specifically, for example, since a SL DRXretransmission timer for monitoring retransmission by the TX UE isstarted after the SL DRX HARQ RTT timer expires, even if SCI does notinclude information related to the second SL resource (i.e., the nextretransmission resource), the RX UE needs to determine the value of theSL DRX HARQ RTT timer to determine the start time of the SL DRXretransmission timer. If the rule for determining the value of the SLDRX HARQ RTT timer is not defined, the understanding of the value of theSL DRX HARQ RTT timer may be different between the TX UE and the RX UE,which may lead to a decrease in reliability of sidelink communication.

Based on various embodiments of the present disclosure, provided are amethod for performing, by the RX UE which has received SCI (includingreserved transmission resource information) and a PSSCH (e.g., SL data)associated with the SCI transmitted by the TX UE, a sidelink powersaving operation based on reserved transmission resource informationincluded in the SCI, and a device supporting the same. Based on variousembodiments of the present disclosure, proposed are a method forobtaining, by the RX UE supporting a sidelink DRX operation, anadditional power saving gain compared to the prior art, if the RX UEreceives SCI (including reserved transmission schedule information)transmitted by the TX UE, and a device supporting the same.

FIG. 9 shows a procedure for an RX UE and/or a TX UE to perform SLcommunication based on a SL DRX configuration, based on an embodiment ofthe present disclosure. The embodiment of FIG. 9 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 9 , in step S910, the TX UE and/or the RX UE mayobtain one or more DRX configurations. For example, the TX UE and/or theRX UE may receive the one or more DRX configurations from the basestation. For example, the one or more DRX configurations may beconfigured or pre-configured for the TX UE and/or the RX UE. Forexample, the one or more DRX configurations may include Uu DRXconfigurations and/or SL DRX configurations.

For example, the Uu DRX configuration may include information related todrx-HARQ-RTT-Timer-SL and/or information related todrx-RetransmissionTimer-SL. For example, the timer may be used for thefollowing purposes.

(1) drx-HARQ-RTT-Timer-SL (per HARQ process): drx-HARQ-RTT-Timer-SL maybe the minimum duration before a sidelink HARQ retransmission grant isexpected by the MAC entity. drx-HARQ-RTT-Timer-SL may refer to theminimum time required until a resource for SL mode 1 retransmission isprepared. That is, the resource for sidelink retransmission cannot beprepared before the drx-HARQ-RTT-Timer-SL timer. Accordingly, the TX UEcan reduce power consumption by transitioning to a sleep mode during thedrx-HARQ-RTT-Time-SL timer. Or, the TX UE may not perform mode 1 DCImonitoring from the base station. If the drx-HARQ-RTT-Timer-SL timerexpires, the TX UE may determine that a resource for SL retransmissionmay be prepared. Accordingly, the TX UE may start thedrx-RetransmissionTimer-SL timer and monitor whether resource(s) for SLHARQ retransmission is received. As soon as the drx-HARQ-RTT-Timer-SLtimer expires, the SL HARQ retransmission resource(s) may or may not bereceived, so the TX UE may start the drx-RetransmissionTimer-SL timer,and the TX UE may monitor mode 1 DCI from the base station to receiveresource(s) for SL HARQ retransmission. For example, thedrx-HARQ-RTT-Timer-SL timer may be a duration in which the TX UEperforming sidelink communication based on sidelink resource allocationmode 1 (e.g., the UE supporting Uu DRX operation) does not perform PDCCH(or DCI) monitoring for sidelink mode 1 resource allocation from thebase station.

(2) drx-RetransmissionTimer-SL (per HARQ process):drx-RetransmissionTimer-SL may be the maximum duration until a grant forsidelink retransmission is received. That is, thedrx-RetransmissionTimer-SL timer may be a timer started when thedrx-HARQ-RTT-Timer-SL timer expires, and it may be a timer that allowsthe TX UE to transition to an active state for SL retransmission. Or,while the corresponding timer is running, the TX UE may monitor mode 1DCI from the base station. The TX UE may start monitoring SL mode 1 DCIfrom the base station, in order to check whether retransmissionresource(s) (i.e., grant for sidelink retransmission) to the RX UE isprepared, from a time when drx-RetransmissionTimer-SL starts. And, ifretransmission resource(s) is prepared, the TX UE may perform sidelinkHARQ retransmission to the RX UE. When transmitting a HARQretransmission packet to the RX UE, the TX UE may stop thedrx-RetransmissionTimer-SL timer. While the drx-RetransmissionTimer-SLtimer is running, the UE may maintain an active state. For example, thedrx-RetransmissionTimer-SL timer may be a duration in which the TX UEperforming sidelink communication based on sidelink resource allocationmode 1 (e.g., the UE supporting Uu DRX operation) performs PDCCH (orDCI) monitoring for sidelink mode 1 resource allocation from the basestation.

For example, the SL DRX configuration may include at least oneparameter/information among parameters/information described below.

(1) SL drx-onDurationTimer: the duration at the beginning of a SL DRXCycle

(2) SL drx-SlotOffset: the delay before starting the sldrx-onDurationTimer

(3) SL drx-InactivityTimer: the duration after the PSCCH occasion inwhich a PSCCH indicates a new SL transmission for the MAC entity

(4) SL drx-StartOffset: the subframe where the SL DRX cycle starts (thesubframe where the SL DRX cycle start)

(5) SL drx-Cycle: SL DRX cycle

(6) SL drx-HARQ-RTT-Timer (per HARQ process or per sidelink process):the minimum duration before an assignment for HARQ retransmission isexpected by the MAC entity the MAC entity)

(7) SL drx-RetransmissionTimer (per HARQ process or per sidelinkprocess): the maximum duration until a retransmission is received

The SL DRX timer described in the present disclosure may be used for thefollowing purposes.

(1) SL DRX onduration timer: the duration in which the UE performing theSL DRX operation should basically operate in an active time in order toreceive a PSCCH/PSSCH from other UE(s)

(2) SL DRX inactivity timer: the duration extending the SL DRXonduration duration, which is the duration in which the UE performingthe SL DRX operation should basically operate in the active time inorder to receive the PSCCH/PSSCH from other UE(s)

For example, the UE may extend the SL DRX onduration timer by the SL DRXinactivity timer duration. In addition, if the UE receives a PSCCH(e.g., 1st SCI and 2^(nd) SCI) for a new transport block (TB) from otherUE(s), or if the UE receives a new packet (e.g., new PSSCH transmission)from other UE(s), the UE may extend the SL DRX onduration timer bystarting the SL DRX inactivity timer.

(3) SL DRX HARQ RTT timer: the duration in which the UE performing theSL DRX operation operates in a sleep mode until receiving aretransmission packet (or PSSCH assignment) transmitted by other UE(s)

For example, if the UE starts the SL DRX HARQ RTT timer, the UE maydetermine that other UE(s) will not transmit a sidelink retransmissionpacket to the UE until the SL DRX HARQ RTT timer expires, and the UE mayoperate in a sleep mode while the corresponding timer is running. Forexample, if the UE starts the SL DRX HARQ RTT timer, the UE maydetermine that the TX UE will not transmit a sidelink retransmissionpacket to the UE until the SL DRX HARQ RTT timer expires, and the UE maynot monitor a sidelink channel/signal transmitted by the TX UE while thecorresponding timer is running.

(4) SL DRX retransmission timer: the timer which starts when the SL DRXHARQ RTT timer expires, and the duration in which the UE performing theSL DRX operation operates in an active time in order to receive aretransmission packet (or PSSCH assignment) transmitted by other UE(s)

For example, for the corresponding timer duration, the UE may receive ormonitor a retransmission sidelink packet (or PSSCH assignment)transmitted by other UE(s).

For example, the SL DRX configuration may include at least one ofinformation related to a SL DRX timer, information related to a SL DRXslot offset, information related to a SL DRX start offset, and/orinformation related to a SL DRX cycle.

For example, the SL DRX timer may include at least one of a SL DRXonduration timer, a SL DRX inactivity timer, a SL DRX retransmissiontimer, and/or a SL DRX HARQ RTT timer. For example, the SL DRXonduration timer may be the duration at the beginning of an SL DRXcycle. For example, the SL DRX inactivity timer may be the durationafter the first slot of SCI reception in which an SCI indicates a new SLtransmission for the MAC entity. For example, the SL DRX retransmissiontimer may be the maximum duration until an SL retransmission isreceived. For example, the SL DRX HARQ RTT timer may be the minimumduration before an SL HARQ retransmission is expected by the MAC entity.For example, the SL DRX retransmission timer and the SL DRX HARQ RTTtimer may be configured per sidelink process. For example, the SL DRXinactivity timer, the SL DRX retransmission timer, and the SL DRX HARQRTT timer may not be applied to broadcast transmission. For example, theUE may start the SL DRX retransmission timer after the SL DRX HARQ RTTtimer expires.

For example, the SL DRX slot offset may be a delay before the start ofthe SL DRX onduration timer. For example, the SL DRX start offset may bethe slot where the SL DRX cycle starts.

For example, a time while at least one of the SL DRX onduration timer,the SL DRX inactivity timer, and/or the SL DRX retransmission timer isrunning may be an active time. However, in various embodiments of thepresent disclosure, the active time is not limited to the time while atleast one of the SL DRX onduration timer, the SL DRX inactivity timer,and/or the SL DRX retransmission timer is running. For example, even ifthe SL DRX onduration timer, the SL DRX inactivity timer, and the SL DRXretransmission timer are not running, the RX UE may operate in an activetime, and the RX UE may monitor a PSCCH from the TX UE.

In the present disclosure, the names of the timer (Uu DRX HARQ RTTTimerSL, Uu DRX Retransmission TimerSL, Sidelink DRX Onduration Timer,Sidelink DRX Inactivity Timer, Sidelink DRX HARQ RTT Timer, Sidelink DRXRetransmission Timer, drx-HARQ-RTT-TimerSL, drx-RetransmissionTimerSL,etc.) is exemplary, and a timer performing the same/similar functionbased on the contents described in each timer may be considered as thesame/similar timer regardless of the names of the timer.

In step S920, the RX UE may receive SCI from the TX UE. For example, theRX UE may receive SCI from the TX UE through a PSCCH. For example, theSCI may include time resource assignment information. For example, thetime resource assignment information may include information related toa resource for current PSSCH transmission and reception. For example,the time resource assignment information may include information relatedto a resource for current PSSCH transmission and reception andinformation related to a resource for next PSSCH transmission andreception (i.e., retransmission resource).

In step S930, the RX UE may receive data from the TX UE. For example,the RX UE may receive data from the TX UE through a PSSCH.

In step S940, the RX UE and/or the TX UE may determine a value of the SLDRX HARQ RTT timer. In step S950, the RX UE may start the SL DRX HARQRTT timer. In addition, based on the expiration of the SL DRX HARQ RTTtimer, the RX UE may start the SL DRX retransmission timer. Throughthis, the RX UE can obtain an additional power saving gain. Hereinafter,a method for determining the value of the SL DRX HARQ RTT timer by theRX UE and/or the TX UE will be described in detail.

Based on an embodiment of the present disclosure, the RX UE may checkinformation (i.e., reserved transmission scheduling information)included in SCI transmitted by the TX UE, and the RX UE may perform apower saving operation by transitioning to a sidelink sleep mode beforereaching the scheduled transmission time. Or, the RX UE may configurethe value of the SL DRX HARQ RTT timer based on reserved transmissionscheduling information included in the SCI.

FIG. 10 shows a method for performing a power saving operation based onresource reservation information included in SCI, based on an embodimentof the present disclosure. The embodiment of FIG. 10 may be combinedwith various embodiments of the present disclosure.

Referring to FIG. 10 , the TX UE may select/reserve resources for up tothree transmissions through SCI, and the TX UE may inform the RX UE ofinformation regarding the resources through the SCI. The RX UE may checktransmission scheduling information (i.e., resource schedulinginformation selected/reserved by the TX UE) included in the SCItransmitted by the TX UE, and the RX UE may infer the time of threetransmissions (1⁴ PSSCH transmission, 2^(nd) PSSCH transmission, 3rdPSSCH transmission) to be performed by the TX UE. Therefore, as in theembodiment of FIG. 10 , the RX UE may perform a power saving operationby transitioning to a sidelink sleep mode (or configuring the value ofthe SL DRX HARQ RTT timer) from the time when the RX UE completesreception of the 1st transmission to the time when the RX UE receivesthe 2^(nd) transmission. In addition, the RX UE may perform the powersaving operation by transitioning to the sidelink sleep mode from thetime when the RX UE completes reception of the 2^(nd) transmission tothe time when the RX UE receives the 3rd transmission.

For example, if the RX UE receives SCI and the received SCI does notinclude resource information for next transmission, the RX UE mayperform a sleep operation. As in the embodiment of FIG. 10 , if the RXUE receives SCI at the location of the 3rd transmission and the receivedSCI does not include resource information for next transmission, the RXUE may set the value of the SL HARQ RTT timer as 0. In this case, the RXUE may immediately start the SL DRX retransmission timer and operate inan active time.

Based on an embodiment of the present disclosure, if the RX UE receivesSCI, the RX UE may perform monitoring for SCI reception in a resourcereservation period information included in the received SCI. In thiscase, the RX UE may fail to receive SCI. For example, if the TX UE failsto perform PSCCH/PSSCH transmission due to pre-emption, re-evaluation,UL-SL prioritization, NR SL-LTE SL prioritization, congestion control,etc., the RX UE may fail to receive SCI in the reserved resource period.Therefore, in this case (in case that the RX UE fails to receive SCI inthe reserved resource period confirmed through the previous SCI), the RXUE may perform the SL DRX operation by setting the value of the SL HARQRTT timer to 0. That is, the RX UE may immediately start the SL DRXretransmission timer and operate in an active time.

Based on an embodiment of the present disclosure, the base station mayinstruct the UE to set the value of the SL HARQ RTT timer based onresource reservation information indicated by SCI. For example, the basestation may instruct the UE to set the value of the SL HARQ RTT timerbased on resource reservation information indicated by SCI through anRRC message. In addition, the base station may instruct the UE to setthe value of the SL HARQ RTT timer to a value of 0 rather than a valueset based on resource reservation information indicated by SCI. Forexample, the base station may instruct the UE through an RRC message toset the value of the SL HARQ RTT timer to a value of 0 rather than avalue set based on resource reservation information indicated by SCI.That is, based on the option indicated by the base station (option 1:setting the value of the SL DRX HARQ RTT timer based on SCI, option 2:setting the value of the SL HARQ RTT timer to 0), the UE may selectwhether to apply the value of the SL HARQ RTT timer configured based onresource reservation information indicated by SCI or the value of the SLHARQ RTT timer configured as 0.

The embodiments of the present disclosure can be equally applied to a SLactive time period (duration in which the UE monitors sidelink channelsor signals) and a SL inactive time period (duration in which the UE doesnot need to monitor sidelink channels or signals, and/or duration inwhich the UE can operate in a power saving mode). Or, the embodiments ofthe present disclosure can be applied even when the UE receives SCI fromother UE(s) at the end of the SL active time and the next transmissionresource reserved through the received SCI at the active time is in theSL inactive time period.

The proposal of the present disclosure can be applied/extended to/as amethod of solving a problem in which loss occurs due to interruptionwhich occurs during Uu BWP switching. In addition, in the case of aplurality of SL BWPs being supported for the UE, the proposal of thepresent disclosure can be applied/extended to/as a method of solving aproblem in which loss occurs due to interruption which occurs during SLBWP switching.

The proposal of the present disclosure can be applied/extended to/asUE-pair specific SL DRX configuration(s), UE-pair specific SL DRXpattern(s) or parameter(s) (e.g., timer) included in UE-pair specific SLDRX configuration(s), as well as default/common SL DRX configuration(s),default/common SL DRX pattern(s), or parameter(s) (e.g., timer) includedin default/common SL DRX configuration(s). In addition, the on-durationmentioned in the proposal of the present disclosure may be extended toor interpreted as an active time (e.g., time to wake-up state (e.g., RFmodule turned on) to receive/transmit radio signal(s)) duration, and theoff-duration may be extended to or interpreted as a sleep time (e.g.,time to sleep in sleep mode state (e.g., RF module turned off) to savepower) duration. It does not mean that the TX UE is obligated to operatein the sleep mode in the sleep time duration. If necessary, the TX UEmay be allowed to operate in an active time for a while for a sensingoperation and/or a transmission operation, even if it is a sleep time.

For example, whether or not the (some) proposed method/rule of thepresent disclosure is applied and/or related parameter(s) (e.g.,threshold value(s)) may be configured (differently or independently) foreach resource pool. For example, whether or not the (some) proposedmethod/rule of the present disclosure is applied and/or relatedparameter(s) (e.g., threshold value(s)) may be configured (differentlyor independently) for each congestion level. For example, whether or notthe (some) proposed method/rule of the present disclosure is appliedand/or related parameter(s) (e.g., threshold value(s)) may be configured(differently or independently) for each service priority. For example,whether or not the (some) proposed method/rule of the present disclosureis applied and/or related parameter(s) (e.g., threshold value(s)) may beconfigured (differently or independently) for each service type. Forexample, whether or not the (some) proposed method/rule of the presentdisclosure is applied and/or related parameter(s) (e.g., thresholdvalue(s)) may be configured (differently or independently) for eachresource pool. For example, whether or not the (some) proposedmethod/rule of the present disclosure is applied and/or relatedparameter(s) (e.g., threshold value(s)) may be configured (differentlyor independently) for each QoS requirement (e.g., latency, reliability).For example, whether or not the (some) proposed method/rule of thepresent disclosure is applied and/or related parameter(s) (e.g.,threshold value(s)) may be configured (differently or independently) foreach PQI (5G QoS identifier (5QI) for PC5). For example, whether or notthe (some) proposed method/rule of the present disclosure is appliedand/or related parameter(s) (e.g., threshold value(s)) may be configured(differently or independently) for each traffic type (e.g., periodicgeneration or aperiodic generation). For example, whether or not the(some) proposed method/rule of the present disclosure is applied and/orrelated parameter(s) (e.g., threshold value(s)) may be configured(differently or independently) for each SL transmission resourceallocation mode (e.g., mode 1 or mode 2). For example, whether or notthe (some) proposed method/rule of the present disclosure is appliedand/or related parameter(s) (e.g., threshold value(s)) may be configured(differently or independently) for each Tx profile (e.g., a Tx profileindicating that a service supports a sidelink DRX operation, and a Txprofile indicating that a service does not need to support a sidelinkDRX operation).

For example, whether or not the proposed rule of the present disclosureis applied and/or related parameter configuration value(s) may beconfigured (differently or independently) for each resource pool (e.g.,resource pool in which PSFCH is configured, resource pool in which PSFCHis not configured). For example, whether or not the proposed rule of thepresent disclosure is applied and/or related parameter configurationvalue(s) may be configured (differently or independently) for eachservice/packet type. For example, whether or not the proposed rule ofthe present disclosure is applied and/or related parameter configurationvalue(s) may be configured (differently or independently) for eachservice/packet priority. For example, whether or not the proposed ruleof the present disclosure is applied and/or related parameterconfiguration value(s) may be configured (differently or independently)for each QoS profile or for each QoS requirement (e.g., URLLC/EMBBtraffic, reliability, latency). For example, whether or not the proposedrule of the present disclosure is applied and/or related parameterconfiguration value(s) may be configured (differently or independently)for each PQI. For example, whether or not the proposed rule of thepresent disclosure is applied and/or related parameter configurationvalue(s) may be configured (differently or independently) for each PFI.For example, whether or not the proposed rule of the present disclosureis applied and/or related parameter configuration value(s) may beconfigured (differently or independently) for each cast type (e.g.,unicast, groupcast, broadcast). For example, whether or not the proposedrule of the present disclosure is applied and/or related parameterconfiguration value(s) may be configured (differently or independently)for each (resource pool) congestion level (e.g., CBR). For example,whether or not the proposed rule of the present disclosure is appliedand/or related parameter configuration value(s) may be configured(differently or independently) for each SL HARQ feedback option (e.g.,NACK-only feedback, ACK/NACK feedback). For example, whether or not theproposed rule of the present disclosure is applied and/or relatedparameter configuration value(s) may be configured specifically (ordifferently or independently) for HARQ Feedback Enabled MAC PDUtransmission. For example, whether or not the proposed rule of thepresent disclosure is applied and/or related parameter configurationvalue(s) may be configured specifically (or differently orindependently) for HARQ Feedback Disabled MAC PDU transmission. Forexample, whether or not the proposed rule of the present disclosure isapplied and/or related parameter configuration value(s) may beconfigured specifically (or differently or independently) according towhether a PUCCH-based SL HARQ feedback reporting operation is configuredor not. For example, whether or not the proposed rule of the presentdisclosure is applied and/or related parameter configuration value(s)may be configured specifically (or differently or independently) forwhether pre-emption is performed. For example, whether or not theproposed rule of the present disclosure is applied and/or relatedparameter configuration value(s) may be configured specifically (ordifferently or independently) for pre-emption-based resourcereselection. For example, whether or not the proposed rule of thepresent disclosure is applied and/or related parameter configurationvalue(s) may be configured specifically (or differently orindependently) for whether re-evaluation is performed. For example,whether or not the proposed rule of the present disclosure is appliedand/or related parameter configuration value(s) may be configuredspecifically (or differently or independently) for re-evaluation-basedresource reselection. For example, whether or not the proposed rule ofthe present disclosure is applied and/or related parameter configurationvalue(s) may be configured (differently or independently) for each (L2or L1) (source and/or destination) identifier. For example, whether ornot the proposed rule of the present disclosure is applied and/orrelated parameter configuration value(s) may be configured (differentlyor independently) for each (L2 or L1) (a combination of source ID anddestination ID) identifier. For example, whether or not the proposedrule of the present disclosure is applied and/or related parameterconfiguration value(s) may be configured (differently or independently)for each (L2 or L1) (a combination of a pair of source ID anddestination ID and a cast type) identifier. For example, whether or notthe proposed rule of the present disclosure is applied and/or relatedparameter configuration value(s) may be configured (differently orindependently) for each direction of a pair of source layer ID anddestination layer ID. For example, whether or not the proposed rule ofthe present disclosure is applied and/or related parameter configurationvalue(s) may be configured (differently or independently) for each PC5RRC connection/link. For example, whether or not the proposed rule ofthe present disclosure is applied and/or related parameter configurationvalue(s) may be configured specifically (or differently orindependently) for the case of performing SL DRX. For example, whetheror not the proposed rule of the present disclosure is applied and/orrelated parameter configuration value(s) may be configured specifically(or differently or independently) for the case of not performing SL DRX.For example, whether or not the proposed rule of the present disclosureis applied and/or related parameter configuration value(s) may beconfigured specifically (or differently or independently) for the caseof supporting SL DRX. For example, whether or not the proposed rule ofthe present disclosure is applied and/or related parameter configurationvalue(s) may be configured specifically (or differently orindependently) for the case of not supporting SL DRX. For example,whether or not the proposed rule of the present disclosure is appliedand/or related parameter configuration value(s) may be configured(differently or independently) for each SL mode type (e.g., resourceallocation mode 1 or resource allocation mode 2). For example, whetheror not the proposed rule of the present disclosure is applied and/orrelated parameter configuration value(s) may be configured specifically(or differently or independently) for the case of performing (a)periodic resource reservation. For example, whether or not the proposedrule of the present disclosure is applied and/or related parameterconfiguration value(s) may be configured specifically (or differently orindependently) for each Tx profile (e.g., a Tx profile indicating that aservice supports a sidelink DRX operation, and a Tx profile indicatingthat a service does not need to support a sidelink DRX operation).

The certain time mentioned in the proposal of the present disclosure mayrefer to a time during which a UE operates in an active time for apre-defined time in order to receive sidelink signal(s) or sidelink datafrom a counterpart UE. The certain time mentioned in the proposal of thepresent disclosure may refer to a time during which a UE operates in anactive time as long as a specific timer (e.g., sidelink DRXretransmission timer, sidelink DRX inactivity timer, or timer to ensurethat an RX UE can operate in an active time in a DRX operation of the RXUE) is running in order to receive sidelink signal(s) or sidelink datafrom a counterpart UE. In addition, the proposal and whether or not theproposal rule of the present disclosure is applied (and/or relatedparameter configuration value(s)) may also be applied to a mmWave SLoperation.

Based on various embodiments of the present disclosure, if SCItransmitted by the TX UE does not include information related to thenext retransmission resource, the RX UE may determine the value of theSL DRX HARQ RTT timer as 0. Through this, it is possible to lower theprobability that the RX UE fails to receive retransmission by the TX UE,and reliability of SL communication between the TX UE and the RX UE canbe guaranteed. Furthermore, if SCI transmitted by the TX UE does notinclude information related to the next retransmission resource, the TXUE may determine/consider that the RX UE sets the value of the SL DRXHARQ RTT timer to 0. Therefore, the TX UE can reserve SL resources or beallocated SL resources within the earliest possible time, and the TX UEmay perform retransmission to the RX UE based on the SL resources.Through this, the latency of SL communication can be reduced, andreliability of SL communication between the TX UE and the RX UE can beguaranteed.

FIG. 11 shows a method for performing wireless communication by a firstdevice, based on an embodiment of the present disclosure. The embodimentof FIG. 11 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 11 , in step S1110, the first device may obtain asidelink (SL) discontinuous reception (DRX) configuration including avalue of a SL DRX retransmission timer. In step S1120, the first devicemay receive, from a second device through a physical sidelink controlchannel (PSCCH), first sidelink control information (SCI) for schedulingof second SCI and a physical sidelink shared channel (PSSCH). In stepS1130, the first device may receive, from the second device through thePSSCH, the second SCI and data. In step S1140, the first device maydetermine a value of a SL DRX hybrid automatic repeat request (HARQ)round trip time (RTT) timer as zero, based on that information relatedto a next retransmission resource is not included in the first SCI. Instep S1150, the first device may start the SL DRX retransmission timer.

For example, the value of the SL DRX HARQ RTT timer may represent aminimum duration before SL HARQ retransmission is expected by the firstdevice.

For example, the value of the SL DRX retransmission timer may representa maximum duration until SL retransmission is received.

For example, the value of the SL DRX retransmission timer and the valueof the SL DRX HARQ RTT timer may be configured per SL process.

Additionally, for example, the first device may start the SL DRX HARQRTT timer in a slot following an end of reception of the PSSCH. Forexample, the SL DRX retransmission timer may be started based onexpiration of the SL DRX HARQ RTT timer.

For example, based on that (i) the information related to the nextretransmission resource is not included in the first SCI and (ii) aphysical sidelink feedback channel (PSFCH) resource is not configured,the value of the SL DRX HARQ RTT timer may be determined as zero.

For example, the first SCI may include information related to timeresource assignment, and the information related to the time resourceassignment may include only time information for the PSSCH.

Additionally, for example, the first device may receive, from a basestation, information for determining the value of the SL DRX HARQ RTTtimer as zero. For example, based on (i) the first SCI not including theinformation related to the next retransmission resource and (ii) theinformation for determining the value of the SL DRX HARQ RTT timer aszero, the value of the SL DRX HARQ RTT timer may be determined as zero.For example, the information for determining the value of the SL DRXHARQ RTT timer as zero may be information related to a SL resource poolfor which a PSFCH is not configured. For example, the information fordetermining the value of the SL DRX HARQ RTT timer as zero may bereceived from the base station through a radio resource control (RRC)message.

For example, a time during which the SL DRX retransmission timer isrunning may be an active time of the first device.

The proposed method can be applied to the device(s) based on variousembodiments of the present disclosure. First, the processor 102 of thefirst device 100 may obtain a sidelink (SL) discontinuous reception(DRX) configuration including a value of a SL DRX retransmission timer.In addition, the processor 102 of the first device 100 may control thetransceiver 106 to receive, from a second device through a physicalsidelink control channel (PSCCH), first sidelink control information(SCI) for scheduling of second SCI and a physical sidelink sharedchannel (PSSCH). In addition, the processor 102 of the first device 100may control the transceiver 106 to receive, from the second devicethrough the PSSCH, the second SCI and data. In addition, the processor102 of the first device 100 may determine a value of a SL DRX hybridautomatic repeat request (HARQ) round trip time (RTT) timer as zero,based on that information related to a next retransmission resource isnot included in the first SCI. In addition, the processor 102 of thefirst device 100 may start the SL DRX retransmission timer.

Based on an embodiment of the present disclosure, a first device adaptedto perform wireless communication may be provided. For example, thefirst device may comprise: one or more memories storing instructions;one or more transceivers; and one or more processors connected to theone or more memories and the one or more transceivers. For example, theone or more processors may execute the instructions to: obtain asidelink (SL) discontinuous reception (DRX) configuration including avalue of a SL DRX retransmission timer; control the one or moretransceivers to receive, from a second device through a physicalsidelink control channel (PSCCH), first sidelink control information(SCI) for scheduling of second SCI and a physical sidelink sharedchannel (PSSCH); control the one or more transceivers to receive, fromthe second device through the PSSCH, the second SCI and data; determinea value of a SL DRX hybrid automatic repeat request (HARQ) round triptime (RTT) timer as zero, based on that information related to a nextretransmission resource is not included in the first SCI; and start theSL DRX retransmission timer.

Based on an embodiment of the present disclosure, a processing deviceadapted to control a first device may be provided. For example, theprocessing device may comprise: one or more processors; and one or morememories operably connected to the one or more processors and storinginstructions. For example, the one or more processors may execute theinstructions to: obtain a sidelink (SL) discontinuous reception (DRX)configuration including a value of a SL DRX retransmission timer;receive, from a second device through a physical sidelink controlchannel (PSCCH), first sidelink control information (SCI) for schedulingof second SCI and a physical sidelink shared channel (PSSCH); receive,from the second device through the PSSCH, the second SCI and data;determine a value of a SL DRX hybrid automatic repeat request (HARQ)round trip time (RTT) timer as zero, based on that information relatedto a next retransmission resource is not included in the first SCI; andstart the SL DRX retransmission timer.

Based on an embodiment of the present disclosure, a non-transitorycomputer readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a first deviceto: obtain a sidelink (SL) discontinuous reception (DRX) configurationincluding a value of a SL DRX retransmission timer; receive, from asecond device through a physical sidelink control channel (PSCCH), firstsidelink control information (SCI) for scheduling of second SCI and aphysical sidelink shared channel (PSSCH); receive, from the seconddevice through the PSSCH, the second SCI and data; determine a value ofa SL DRX hybrid automatic repeat request (HARQ) round trip time (RTT)timer as zero, based on that information related to a nextretransmission resource is not included in the first SCI; and start theSL DRX retransmission timer.

FIG. 12 shows a method for performing wireless communication by a seconddevice, based on an embodiment of the present disclosure. The embodimentof FIG. 12 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 12 , in step S1210, the second device may obtain asidelink (SL) discontinuous reception (DRX) configuration including avalue of a SL DRX retransmission timer. In step S1220, the second devicemay transmit, to a first device through a physical sidelink controlchannel (PSCCH), first sidelink control information (SCI) for schedulingof second SCI and a physical sidelink shared channel (PSSCH). In stepS1230, the second device may transmit, to the first device through thePSSCH, the second SCI and data. In step S1240, the second device maydetermine, based on that information related to a next retransmissionresource is not included in the first SCI, that the first device sets avalue of a SL DRX hybrid automatic repeat request (HARQ) round trip time(RTT) timer to zero.

The proposed method can be applied to the device(s) based on variousembodiments of the present disclosure. First, the processor 202 of thesecond device 200 may obtain a sidelink (SL) discontinuous reception(DRX) configuration including a value of a SL DRX retransmission timer.In addition, the processor 202 of the second device 200 may control thetransceiver 206 to transmit, to a first device through a physicalsidelink control channel (PSCCH), first sidelink control information(SCI) for scheduling of second SCI and a physical sidelink sharedchannel (PSSCH). In addition, the processor 202 of the second device 200may control the transceiver 206 to transmit, to the first device throughthe PSSCH, the second SCI and data. In addition, the processor 202 ofthe second device 200 may determine, based on that information relatedto a next retransmission resource is not included in the first SCI, thatthe first device sets a value of a SL DRX hybrid automatic repeatrequest (HARQ) round trip time (RTT) timer to zero.

Based on an embodiment of the present disclosure, a second deviceadapted to perform wireless communication may be provided. For example,the second device may comprise: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers.For example, the one or more processors may execute the instructions to:obtain a sidelink (SL) discontinuous reception (DRX) configurationincluding a value of a SL DRX retransmission timer; control the one ormore transceivers to transmit, to a first device through a physicalsidelink control channel (PSCCH), first sidelink control information(SCI) for scheduling of second SCI and a physical sidelink sharedchannel (PSSCH); control the one or more transceivers to transmit, tothe first device through the PSSCH, the second SCI and data; anddetermine, based on that information related to a next retransmissionresource is not included in the first SCI, that the first device sets avalue of a SL DRX hybrid automatic repeat request (HARQ) round trip time(RTT) timer to zero.

Based on an embodiment of the present disclosure, a processing deviceadapted to control a second device may be provided. For example, theprocessing device may comprise: one or more processors; and one or morememories operably connected to the one or more processors and storinginstructions. For example, the one or more processors may execute theinstructions to: obtain a sidelink (SL) discontinuous reception (DRX)configuration including a value of a SL DRX retransmission timer;transmit, to a first device through a physical sidelink control channel(PSCCH), first sidelink control information (SCI) for scheduling ofsecond SCI and a physical sidelink shared channel (PSSCH); transmit, tothe first device through the PSSCH, the second SCI and data; anddetermine, based on that information related to a next retransmissionresource is not included in the first SCI, that the first device sets avalue of a SL DRX hybrid automatic repeat request (HARQ) round trip time(RTT) timer to zero.

Based on an embodiment of the present disclosure, a non-transitorycomputer readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a second deviceto: obtain a sidelink (SL) discontinuous reception (DRX) configurationincluding a value of a SL DRX retransmission timer; transmit, to a firstdevice through a physical sidelink control channel (PSCCH), firstsidelink control information (SCI) for scheduling of second SCI and aphysical sidelink shared channel (PSSCH); transmit, to the first devicethrough the PSSCH, the second SCI and data; and determine, based on thatinformation related to a next retransmission resource is not included inthe first SCI, that the first device sets a value of a SL DRX hybridautomatic repeat request (HARQ) round trip time (RTT) timer to zero.

Various embodiments of the present disclosure may be combined with eachother.

Hereinafter, device(s) to which various embodiments of the presentdisclosure can be applied will be described.

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the present disclosure described inthis document may be applied to, without being limited to, a variety offields requiring wireless communication/connection (e.g., 5G) betweendevices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 13 shows a communication system 1, based on an embodiment of thepresent disclosure. The embodiment of FIG. 13 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 13 , a communication system 1 to which variousembodiments of the present disclosure are applied includes wirelessdevices, Base Stations (BSs), and a network. Herein, the wirelessdevices represent devices performing communication using Radio AccessTechnology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE))and may be referred to as communication/radio/5G devices. The wirelessdevices may include, without being limited to, a robot 100 a, vehicles100 b-1 and 100 b-2, an eXtended Reality (XR) device 100 c, a hand-helddevice 100 d, a home appliance 100 e, an Internet of Things (IoT) device100 f, and an Artificial Intelligence (AI) device/server 400. Forexample, the vehicles may include a vehicle having a wirelesscommunication function, an autonomous vehicle, and a vehicle capable ofperforming communication between vehicles. Herein, the vehicles mayinclude an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR devicemay include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality(MR) device and may be implemented in the form of a Head-Mounted Device(HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, asmartphone, a computer, a wearable device, a home appliance device, adigital signage, a vehicle, a robot, etc. The hand-held device mayinclude a smartphone, a smartpad, a wearable device (e.g., a smartwatchor a smartglasses), and a computer (e.g., a notebook). The homeappliance may include a TV, a refrigerator, and a washing machine. TheIoT device may include a sensor and a smartmeter. For example, the BSsand the network may be implemented as wireless devices and a specificwireless device 200 a may operate as a BS/network node with respect toother wireless devices.

Here, wireless communication technology implemented in wireless devices100 a to 100 f of the present disclosure may include Narrowband Internetof Things for low-power communication in addition to LTE, NR, and 6G. Inthis case, for example, NB-IoT technology may be an example of Low PowerWide Area Network (LPWAN) technology and may be implemented as standardssuch as LTE Cat NB1, and/or LTE Cat NB2, and is not limited to the namedescribed above. Additionally or alternatively, the wirelesscommunication technology implemented in the wireless devices 100 a to100 f of the present disclosure may perform communication based on LTE-Mtechnology. In this case, as an example, the LTE-M technology may be anexample of the LPWAN and may be called by various names includingenhanced Machine Type Communication (eMTC), and the like. For example,the LTE-M technology may be implemented as at least any one of variousstandards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTEnon-Bandwidth Limited (non-BL), 5) LTE-MTC, 6) LTE Machine TypeCommunication, and/or 7) LTE M, and is not limited to the name describedabove. Additionally or alternatively, the wireless communicationtechnology implemented in the wireless devices 100 a to 100 f of thepresent disclosure may include at least one of Bluetooth, Low Power WideArea Network (LPWAN), and ZigBee considering the low-powercommunication, and is not limited to the name described above. As anexample, the ZigBee technology may generate personal area networks (PAN)related to small/low-power digital communication based on variousstandards including IEEE 802.15.4, and the like, and may be called byvarious names.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g. relay, Integrated AccessBackhaul (TAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 14 shows wireless devices, based on an embodiment of the presentdisclosure. The embodiment of FIG. 14 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 14 , a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 13 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports).

The one or more transceivers 106 and 206 may convert received radiosignals/channels etc. from RF band signals into baseband signals inorder to process received user data, control information, radiosignals/channels, etc. using the one or more processors 102 and 202. Theone or more transceivers 106 and 206 may convert the user data, controlinformation, radio signals/channels, etc. processed using the one ormore processors 102 and 202 from the base band signals into the RF bandsignals. To this end, the one or more transceivers 106 and 206 mayinclude (analog) oscillators and/or filters.

FIG. 15 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure. The embodiment of FIG. 15may be combined with various embodiments of the present disclosure.

Referring to FIG. 15 , a signal processing circuit 1000 may includescramblers 1010, modulators 1020, a layer mapper 1030, a precoder 1040,resource mappers 1050, and signal generators 1060. An operation/functionof FIG. 15 may be performed, without being limited to, the processors102 and 202 and/or the transceivers 106 and 206 of FIG. 14 . Hardwareelements of FIG. 15 may be implemented by the processors 102 and 202and/or the transceivers 106 and 206 of FIG. 14 . For example, blocks1010 to 1060 may be implemented by the processors 102 and 202 of FIG. 14. Alternatively, the blocks 1010 to 1050 may be implemented by theprocessors 102 and 202 of FIG. 14 and the block 1060 may be implementedby the transceivers 106 and 206 of FIG. 14 .

Codewords may be converted into radio signals via the signal processingcircuit 1000 of FIG. 15 . Herein, the codewords are encoded bitsequences of information blocks. The information blocks may includetransport blocks (e.g., a UL-SCH transport block, a DL-SCH transportblock). The radio signals may be transmitted through various physicalchannels (e.g., a PUSCH and a PDSCH).

Specifically, the codewords may be converted into scrambled bitsequences by the scramblers 1010. Scramble sequences used for scramblingmay be generated based on an initialization value, and theinitialization value may include ID information of a wireless device.The scrambled bit sequences may be modulated to modulation symbolsequences by the modulators 1020. A modulation scheme may includepi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying(m-PSK), and m-Quadrature Amplitude Modulation (m-QAM). Complexmodulation symbol sequences may be mapped to one or more transportlayers by the layer mapper 1030. Modulation symbols of each transportlayer may be mapped (precoded) to corresponding antenna port(s) by theprecoder 1040. Outputs z of the precoder 1040 may be obtained bymultiplying outputs y of the layer mapper 1030 by an N*M precodingmatrix W.

Herein, N is the number of antenna ports and M is the number oftransport layers. The precoder 1040 may perform precoding afterperforming transform precoding (e.g., DFT) for complex modulationsymbols. Alternatively, the precoder 1040 may perform precoding withoutperforming transform precoding.

The resource mappers 1050 may map modulation symbols of each antennaport to time-frequency resources. The time-frequency resources mayinclude a plurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMAsymbols) in the time domain and a plurality of subcarriers in thefrequency domain. The signal generators 1060 may generate radio signalsfrom the mapped modulation symbols and the generated radio signals maybe transmitted to other devices through each antenna. For this purpose,the signal generators 1060 may include Inverse Fast Fourier Transform(IFFT) modules, Cyclic Prefix (CP) inserters, Digital-to-AnalogConverters (DACs), and frequency up-converters.

Signal processing procedures for a signal received in the wirelessdevice may be configured in a reverse manner of the signal processingprocedures 1010 to 1060 of FIG. 15 . For example, the wireless devices(e.g., 100 and 200 of FIG. 14 ) may receive radio signals from theexterior through the antenna ports/transceivers. The received radiosignals may be converted into baseband signals through signal restorers.To this end, the signal restorers may include frequency downlinkconverters, Analog-to-Digital Converters (ADCs), CP remover, and FastFourier Transform (FFT) modules. Next, the baseband signals may berestored to codewords through a resource demapping procedure, apostcoding procedure, a demodulation processor, and a descramblingprocedure. The codewords may be restored to original information blocksthrough decoding. Therefore, a signal processing circuit (notillustrated) for a reception signal may include signal restorers,resource demappers, a postcoder, demodulators, descramblers, anddecoders.

FIG. 16 shows another example of a wireless device, based on anembodiment of the present disclosure. The wireless device may beimplemented in various forms according to a use-case/service (refer toFIG. 13 ). The embodiment of FIG. 16 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 16 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 14 and may be configured byvarious elements, components, units/portions, and/or modules. Forexample, each of the wireless devices 100 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 14 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 14 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and controlsoverall operation of the wireless devices. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/commands/information stored in the memory unit130. The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g., other communication devices) viathe communication unit 110 through a wireless/wired interface or store,in the memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 13 ), the vehicles (100 b-1 and 100 b-2 of FIG. 13 ), the XRdevice (100 c of FIG. 13 ), the hand-held device (100 d of FIG. 13 ),the home appliance (100 e of FIG. 13 ), the IoT device (100 f of FIG. 13), a digital broadcast terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 13 ), the BSs (200 of FIG. 13 ), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 16 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 16 will be described indetail with reference to the drawings.

FIG. 17 shows a hand-held device, based on an embodiment of the presentdisclosure. The hand-held device may include a smartphone, a smartpad, awearable device (e.g., a smartwatch or a smartglasses), or a portablecomputer (e.g., a notebook). The hand-held device may be referred to asa mobile station (MS), a user terminal (UT), a Mobile Subscriber Station(MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or aWireless Terminal (WT). The embodiment of FIG. 17 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 17 , a hand-held device 100 may include an antennaunit 108, a communication unit 110, a control unit 120, a memory unit130, a power supply unit 140 a, an interface unit 140 b, and an I/O unit140 c. The antenna unit 108 may be configured as a part of thecommunication unit 110. Blocks 110 to 130/140 a to 140 c correspond tothe blocks 110 to 130/140 of FIG. 16 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g., touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

FIG. 18 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure. The vehicle or autonomous vehicle may beimplemented by a mobile robot, a car, a train, a manned/unmanned AerialVehicle (AV), a ship, etc. The embodiment of FIG. 18 may be combinedwith various embodiments of the present disclosure.

Referring to FIG. 18 , a vehicle or autonomous vehicle 100 may includean antenna unit 108, a communication unit 110, a control unit 120, adriving unit 140 a, a power supply unit 140 b, a sensor unit 140 c, andan autonomous driving unit 140 d. The antenna unit 108 may be configuredas a part of the communication unit 110. The blocks 110/130/140 a to 140d correspond to the blocks 110/130/140 of FIG. 16 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous vehicle 100. The control unit 120 may includean Electronic Control Unit (ECU). The driving unit 140 a may cause thevehicle or the autonomous vehicle 100 to drive on a road. The drivingunit 140 a may include an engine, a motor, a powertrain, a wheel, abrake, a steering device, etc. The power supply unit 140 b may supplypower to the vehicle or the autonomous vehicle 100 and include awired/wireless charging circuit, a battery, etc. The sensor unit 140 cmay acquire a vehicle state, ambient environment information, userinformation, etc. The sensor unit 140 c may include an InertialMeasurement Unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, a slope sensor, a weight sensor, a heading sensor, aposition module, a vehicle forward/backward sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a pedalposition sensor, etc. The autonomous driving unit 140 d may implementtechnology for maintaining a lane on which a vehicle is driving,technology for automatically adjusting speed, such as adaptive cruisecontrol, technology for autonomously driving along a determined path,technology for driving by automatically setting a path if a destinationis set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous vehicle 100 may movealong the autonomous driving path according to the driving plan (e.g.,speed/direction control). In the middle of autonomous driving, thecommunication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous vehicles and provide the predicted traffic information datato the vehicles or the autonomous vehicles.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod.

What is claimed is:
 1. A method for performing wireless communication bya first device, the method comprising: obtaining a sidelink (SL)discontinuous reception (DRX) configuration including a value of a SLDRX retransmission timer; receiving, from a second device through aphysical sidelink control channel (PSCCH), first sidelink controlinformation (SCI) for scheduling of second SCI and a physical sidelinkshared channel (PSSCH); receiving, from the second device through thePSSCH, the second SCI and data; determining a value of a SL DRX hybridautomatic repeat request (HARQ) round trip time (RTT) timer as zero,based on that information related to a next retransmission resource isnot included in the first SCI; and starting the SL DRX retransmissiontimer.
 2. The method of claim 1, wherein the value of the SL DRX HARQRTT timer represents a minimum duration before SL HARQ retransmission isexpected by the first device.
 3. The method of claim 1, wherein thevalue of the SL DRX retransmission timer represents a maximum durationuntil SL retransmission is received.
 4. The method of claim 1, whereinthe value of the SL DRX retransmission timer and the value of the SL DRXHARQ RTT timer are configured per SL process.
 5. The method of claim 1,further comprising: starting the SL DRX HARQ RTT timer in a slotfollowing an end of reception of the PSSCH.
 6. The method of claim 5,wherein the SL DRX retransmission timer is started based on expirationof the SL DRX HARQ RTT timer.
 7. The method of claim 1, wherein, basedon that (i) the information related to the next retransmission resourceis not included in the first SCI and (ii) a physical sidelink feedbackchannel (PSFCH) resource is not configured, the value of the SL DRX HARQRTT timer is determined as zero.
 8. The method of claim 1, wherein thefirst SCI includes information related to time resource assignment, andwherein the information related to the time resource assignment includesonly time information for the PSSCH.
 9. The method of claim 1, furthercomprising: receiving, from a base station, information for determiningthe value of the SL DRX HARQ RTT timer as zero.
 10. The method of claim9, wherein, based on (i) the first SCI not including the informationrelated to the next retransmission resource and (ii) the information fordetermining the value of the SL DRX HARQ RTT timer as zero, the value ofthe SL DRX HARQ RTT timer is determined as zero.
 11. The method of claim10, wherein the information for determining the value of the SL DRX HARQRTT timer as zero is information related to a SL resource pool for whicha PSFCH is not configured.
 12. The method of claim 9, wherein theinformation for determining the value of the SL DRX HARQ RTT timer aszero is received from the base station through a radio resource control(RRC) message.
 13. The method of claim 1, wherein a time during whichthe SL DRX retransmission timer is running is an active time of thefirst device.
 14. A first device adapted to perform wirelesscommunication, the first device comprising: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers,wherein the one or more processors execute the instructions to: obtain asidelink (SL) discontinuous reception (DRX) configuration including avalue of a SL DRX retransmission timer; control the one or moretransceivers to receive, from a second device through a physicalsidelink control channel (PSCCH), first sidelink control information(SCI) for scheduling of second SCI and a physical sidelink sharedchannel (PSSCH); control the one or more transceivers to receive, fromthe second device through the PSSCH, the second SCI and data; determinea value of a SL DRX hybrid automatic repeat request (HARQ) round triptime (RTT) timer as zero, based on that information related to a nextretransmission resource is not included in the first SCI; and start theSL DRX retransmission timer.
 15. The first device of claim 14, whereinthe value of the SL DRX HARQ RTT timer represents a minimum durationbefore SL HARQ retransmission is expected by the first device.
 16. Thefirst device of claim 14, wherein the value of the SL DRX retransmissiontimer represents a maximum duration until SL retransmission is received.17. The first device of claim 14, wherein the value of the SL DRXretransmission timer and the value of the SL DRX HARQ RTT timer areconfigured per SL process.
 18. A processing device adapted to control afirst device, the processing device comprising: one or more processors;and one or more memories operably connected to the one or moreprocessors and storing instructions, wherein the one or more processorsexecute the instructions to: obtain a sidelink (SL) discontinuousreception (DRX) configuration including a value of a SL DRXretransmission timer; receive, from a second device through a physicalsidelink control channel (PSCCH), first sidelink control information(SCI) for scheduling of second SCI and a physical sidelink sharedchannel (PSSCH); receive, from the second device through the PSSCH, thesecond SCI and data; determine a value of a SL DRX hybrid automaticrepeat request (HARQ) round trip time (RTT) timer as zero, based on thatinformation related to a next retransmission resource is not included inthe first SCI; and start the SL DRX retransmission timer.
 19. Theprocessing device of claim 18, wherein the value of the SL DRX HARQ RTTtimer represents a minimum duration before SL HARQ retransmission isexpected by the first device.
 20. The processing device of claim 18,wherein the value of the SL DRX retransmission timer represents amaximum duration until SL retransmission is received.